June 30th, 2022

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Chronic Abruption-Oligohydramnios Sequence
Authors:  John P. Elliott, M.D., Brian Gilpin, M.D., Thomas H. Strong, Jr., M.D., and Harris J. Finberg, M.D.
  OBJECTIVE: To determine outcome in patients with
chronic abruption.

STUDY DESIGN: A retrospective review was performed
of all patients delivering
at a tertiary medical center
during a 54-month
period. All patients with a diagnosis
of placental abruption
with oligohydramnios or
ruptured membranes were
included. Chronic abruption-
oligohydramnios sequence
(CAOS) was defined
by the following criteria: (1)
clinically significant vaginal bleeding in the absence of
placenta previa or other identifiable source of bleeding,
(2) amniotic fluid volume initially documented as normal,
and (3) oligohydramnios (amniotic fluid index ≤ 5)
eventually developing without concurrent evidence of
ruptured membranes.

RESULTS: Twenty-four patients with CAOS were identified.
Fourteen had first evidence of abruption at < 20
weeks‘ gestational age. A clot was identified between the
chorion and uterus in 18/24. The mean gestational age at
the first bleeding episode was 19.4±5.5 (SD) weeks, with
the mean gestational age at delivery 28.1±4.5 weeks.
Preterm premature membrane rupture occurred in
15/24. In these 15 there was a mean of 11.5± days between
the diagnosis of oligohydramnios and of ruptured
membranes. Patients whose first blood occurred at < 20
weeks‘ gestation delivered at a gestational age of
26.1±3.9 weeks versus 33.0±5.3 weeks for the control

CONCLUSION: CAOS can occur in pregnancies complicated
by abruptio placentae.
If it develops, the mean gestational age at delivery is 28 weeks. (J Reprod Med 1998;43:418-422)
Keywords:  abruptio placentae, oligohydramnios, pregnancy complications, CAOS
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